Method and apparatus for recycling lithium iron phosphate batteries

ABSTRACT

Cathode material from exhausted lithium ion batteries are dissolved in a solution for extracting the useful elements Co (cobalt), Ni (nickel), Al (Aluminum) and Mn (manganese) to produce active cathode materials for new batteries. The solution includes compounds of valuable charge materials such as cobalt, nickel, aluminum and manganese dissolved as compounds from the exhausted cathode material of spent cells. However, LiFePO4 is a waste stream charge material often discarded due to infeasibility of recycling. LiFePO4 is precipitated as FePO4 and remains as a by-product, along with graphite and carbon, which are not dissolved into the solution. FePO4 can be separated from graphite and carbon, FePO4 can be used to synthesize LiFePO4 as cathode materials and graphite can be regenerated as anode materials.

RELATED APPLICATIONS

This patent application claims the benefit under 35 U.S.C. § 119(e) ofU.S. Provisional Patent App. No. 62/504,699, filed May 11, 2017,entitled “METHOD OF RECOVERING LiFePO4 AND GRAPHITE FROM LITHIUM IONBATTERIES,” and is a Continuation-in-Part (CIP) of U.S. patentapplication Ser. No. 15/358,862, filed Nov. 22, 2016, which claims thebenefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent App. No.62/259,161, filed Nov. 24, 2015, entitled “METHOD AND APPARATUS FORRECYCLING LITHIUM-ION BATTERIES,” and is a Continuation-in-Part (CIP) ofU.S. patent application Ser. No. 13/855,994, filed Apr. 3, 2013,entitled “METHOD AND APPARATUS FOR RECYCLING LITHIUM-ION BATTERIES,” nowU.S. Pat. No. 9,834,827, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent App. No. 61/620,051, filed Apr. 4,2012, entitled “FULL CLOSED LOOP FOR RECYCLING LITHIUM ION BATTERIES,”all incorporated herein by reference in entirety.

BACKGROUND

For decades, portable electrical power supplies have taken the form ofbatteries that release electrical energy from an electrochemicalreaction. Various battery chemistries, such as traditional “dry cell”carbon flashlight batteries, and lead acid “wet” cells common inautomobiles have provided adequate portable electrical power. Modernelectronics, however, place significantly greater demands on thelongevity and mass of batteries. Battery power has traditionally come ata premium of the mass required for the charge material for generatingsufficient current. Conventional flashlight batteries deliver only lowcurrent. Automobile batteries for delivering an intense but brief highamperage flow to a starter motor are very dense and large. Modernelectronic devices, such as cell phones, computing devices, andautomobiles, demand substantial current delivery while being lightweightand small enough to avoid hindering the portability of the host device.

Rechargeable nickel-cadmium (NiCad) and nickel metal hydride (NiMH) hadgained popularity for rechargeable batteries for portable devices.Recently, however, advances in lithium-ion batteries (LIBs) have beensignificant such that they have become the most popular power source forportable electronics equipment, and are also growing in popularity formilitary, electric vehicle, and aerospace applications. Continuingdevelopment of personnel electronics, hybrid and electric vehicles,ensures that Li-ion batteries will continue to be increasingly indemand.

SUMMARY

Exhausted LIBs undergo a physical separation process for removing solidbattery components, such as casing and plastics, and electrodes aredissolved in a solution for extracting the useful elements Co (cobalt),Ni (nickel), Mn (manganese), and Li (lithium), from mixed cathodematerials and utilizing the recycled elements to produce activematerials for new batteries. Configurations herein are based, in part,on the observation that conventional approaches do not recycle andrecover Li-ion batteries with LiNiCoAlO₂, which is being used inautomobile application (for example Tesla™ electric vehicles).

The solution includes compounds of desirable materials such as cobalt,nickel and manganese dissolved as compounds from the exhausted cathodematerial of spent cells. Depending on a desired proportion, or ratio, ofthe desired materials, raw materials are added to the solution toachieve the desired ratio of the commingled compounds for the recycledcathode material for new cells. A strong base, such as sodium hydroxide,raises the pH such that the desired materials precipitate out ofsolution without extensive heating or separation of the desiredmaterials into individual compounds or elements. The resulting activecathode material has the predetermined ratio for use in new cells, andavoids high heat typically required to separate the useful elementsbecause the desired materials remain commingled in solution and undergoonly a change in concentration (ratio) by adding small amounts of purecharge material to achieve a target composition.

Lithium-ion batteries, like their NiCd (nickel-cadmium) and NiMH(nickel-metal hydride) predecessors, have a finite number of chargecycles. It is therefore expected that LIBs will become a significantcomponent of the solid waste stream, as numerous electric vehicles reachthe end of their lifespan. Recycling of the charge material in thelithium batteries both reduces waste volume and yields active chargematerial for new batteries.

Recycling can dramatically reduce the required lithium amount. Variouschemicals in lithium ion batteries include valuable metals such ascobalt, manganese, and nickel. Additionally, battery disposal wouldrequire that fresh metals be mined for cathode material, and mining hasa much bigger environmental impact and cost than simple recycling would.In short, recycling of lithium ion batteries not only protects theenvironment and saves energy, but also presents a lucrative outlet forbattery manufacturers by providing an inexpensive supply of activecathode material for new batteries.

Current recycling procedures for Li-ion cells are generally focused onLiCoO₂ cathode materials. Although some posted their methods to recyclemore kinds of cathode materials, all are complex and not necessarilyeconomical or practical. A simple methodology with high efficiency isproposed in order to recycle Li-ion batteries economically and withindustrial viability. The disclosed approach results in synthesis ofcathode materials (particularly valuable in Li-ion batteries) fromrecycled components. In contrast to conventional approaches, thedisclosed approach does not separate Ni, Mn, and Co out. Instead,uniform-phase precipitation is employed as starting materials tosynthesize the cathode materials as active charge material suitable fornew batteries. The analytical results showed that the recycling processis practical and has high recovery efficiency, and has commercial valueas well.

Configurations herein are based, in part, on the observation that theincreasing popularity of lithium ion cells as a source of portableelectric power will result in a corresponding increase in spentlithium-based cathode material as the deployed cells reach the end oftheir useful lifetime. While 97% of lead acid batteries are recycled,such that over 50 percent of the lead supply comes from recycledbatteries, lithium ion batteries are not yet being recycled widely.While the projected increase of lithium demand is substantial, analysisof Lithium's geological resource base shows that there is insufficientlithium available in the Earth's crust to sustain electric vehiclemanufacture in the volumes required, based solely on Li-ion batteries.Recycling can dramatically reduce the required lithium amount. Arecycling infrastructure will ease concerns that the adoption ofvehicles that use lithium-ion batteries could lead to a shortage oflithium carbonate and a dependence on countries rich in the supply ofglobal lithium reserves.

Unfortunately, conventional approaches to the above approaches sufferfrom the shortcoming that recycling approaches include high temperatureprocesses to separate the compounds of the desirable materials ofcobalt, manganese, nickel and lithium. This high-temperature processresults in breaking down the compounds for separation, but only torecombine them again for new active material. The high temperatureapproach therefore requires substantial energy, expense, and processingfor separating and recombining the desirable materials.

Accordingly, configurations herein substantially overcome the describedshortcoming of heat intensive component separation described above bygenerating a low temperature solution of the desired compounds that ismixed with small amounts of additional pure forms of the desirablematerials to achieve a target ratio of the desired active chargematerials. The desirable materials are extracted by precipitation toresult in recycled active cathode material without separating orbreaking down the compounds, allowing a lower temperature and lessexpensive process to generate the active cathode materials.

The solution includes recovering active materials from lithium ionbatteries with LiNiCoAlO₂ chemistry in a manner that can be used to makenew active materials for new lithium ion batteries. To date,conventional approaches cannot recover transition metals from LiNiCoAlO2in such a form that they can be used to make new cathode materials forLNiCoO2 or LiNiCoAlO2 batteries without using expensive organicreagents. The recovered precursor material NiCoAl(OH)₂ or NiCo(OH)₂ canbe used for making new LiNiCoAlO₂ or LiNiCoO₂ cathode materials. Thismay include adding Al(OH)₃ to the precipitated material and/or Ni, Co,or Al sulfates to the solution prior to precipitation.

In the proposed approach, it is desirable that the batteries be of asingle stream chemistry (LiNiCoAlO₂) however if there are otherchemistries present in the LiMO₂ (where M is manganese, as well as Ni,Al and Co), the manganese can be removed from solution. Ni, Co and Alcan be used to precipitate precursor and synthesize cathode materials.

It is likely that cells of various chemistries will appear in therecycling stream. In particular, LiFePO₄ is received and recycled byalternate configurations disclosed below. However, LiFePO₄ is a wastestream charge material often discarded due to infeasibility ofrecycling. In configurations disclosed herein, LiFePO₄ is precipitatedas FePO4 and remains as a by-product, along with graphite and carbon,which are not dissolved into the solution. FePO₄ can be separated fromgraphite and carbon, FePO₄ can be used to synthesize LiFePO₄ andgraphite can be regenerated.

The claimed approach, outlined in more detail below, defines a method ofrecycling Li ion batteries including generating a solution of aggregatebattery materials from spent cells, and precipitating impurities fromthe generated solution to result in a charge material precursor.Materials are added to adjust the solution to achieve a predeterminedratio of desirable materials based on desired chemistry of the newbatteries. Lithium carbonate is introduced and sintered to form cathodematerials in the form of LiNi_(x)Co_(y)Al_(z)O₂. Adjusting the desirablematerials includes the addition of at least one of Ni, Co or Al, andtypically the addition of desirable materials is in the form of salts orions.

In the approach disclosed below, a method of recycling Li-ion batteriestherefore includes generating a solution of aggregate battery materialsfrom spent cells, and precipitating mixtures from the generatedsolution. A recycler apparatus adjusts the solution to achieve apredetermined ratio of desirable materials, and precipitating thedesirable material in the predetermined ratio to form cathode materialfor a new battery having the predetermined ratio of the desirablematerials. It should be noted that although the methods and apparatusdisclosed herein employ Li-ion batteries as an example, the principlesare intended as illustrative and could be applied to other types ofcathode materials suited to other battery chemistries.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features will be apparent from the followingdescription of particular embodiments disclosed herein, as illustratedin the accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 is a context diagram of a battery recycling environment suitablefor use with configurations herein;

FIG. 2 is a flowchart of lithium battery recycling in the environment ofFIG. 1;

FIG. 3 is a diagram of charge flow (electrons) during charging anddischarging of the batteries of FIG. 1;

FIG. 4 is a diagram of battery structure of the batteries of FIG. 1;

FIG. 5 is a diagram of recycling the cathode material in the battery ofFIG. 4;

FIG. 6 is a process flow diagram of recycling lithium-aluminum ionbatteries;

FIG. 7 is a process flow for an alternate configuration of recyclinglithium-aluminum batteries using aluminum hydroxide;

FIG. 8 is a process flow diagram for a combined recycling process forboth Ni/Mn/Co (NMC) and Ni/Co/Al (NCA) batteries for any suitable molarratio;

FIG. 9 shows an alternative configuration for processing residual chargematerial as in FIG. 8; and

FIGS. 10a-b are a flowchart for recycling lithium iron phosphate(LiFePO₄) from the residual charge material of FIG. 9.

DETAILED DESCRIPTION

Depicted below is an example method and apparatus for recyclingbatteries such as lithium ion batteries. The proposed approach is anexample and is applicable to other lithium and non-lithium batteries forrecycling spent batteries and recovering active cathode materialsuitable for use in new batteries. FIG. 1 is a context diagram of abattery recycling environment 100 suitable for use with configurationsherein. Referring to FIG. 1, in the battery recycling environment 100,electronic devices 110 such as laptops, automobiles (hybrid and pureelectric), computers, smartphones, and any other type of batterysupported equipment is suitable for use with the disclosed approach. Theelectronic devices contribute spent cells 120, having exhausted cathodematerial 122 that nonetheless includes the raw materials responsive tothe recycling approach discussed herein. A physical separation process124 dismantles the battery to form a granular mass 126 of the exhaustedbattery material including the raw materials in particulate form,usually by simply crushing and grinding the spent battery casings andcells therein.

Physical separation is applied to remove the battery cases (plastic) andelectrode materials, often via magnetic separation that draws out themagnetic steel. A recycler 130 includes physical containment of asolution 141 including the remaining granular mass 126 from the spentcharge materials, typically taking the form of a powder from theagitated (crushed) spent batteries. Additional raw materials 142 areadded to achieve a predetermined ratio of the desirable materials in thesolution 141. Following the recycling process, as discussed furtherbelow, active charge materials 134 result and are employed to form newcells 140 including the recycled cathode material 132. The new cells 140may then be employed in the various types of devices 110 thatcontributed the exhausted, spent cells 120. The recycler may include anapparatus for containing the solution 141 such that a pH adjuster ormodifier and raw materials may be added to the solution 141.

FIG. 2 is a flowchart of lithium battery recycling in the environment ofFIG. 1. Referring to FIGS. 1 and 2, the method of recycling cathodematerial 122 as disclosed herein includes generating a solution 141 fromcathode materials derived from exhausted battery cells 120, as depictedat step 200. The method combines additional raw material 142 to achievea predetermined ratio of the materials in solution 141, and is such thatthe solution temperature is maintained sufficiently low for avoidinghigh temperature process common in conventional recycling approaches.The solution 141 precipitates the precursor materials 134 by increasingthe pH of the solution 141, such that the precipitated materials 134have the predetermined ratio and having suitable proportion for use tosynthesize the cathode material 132 for the new battery cells 140. Inthe example configuration, the desirable materials include manganese(Mn), cobalt (Co), and nickel (Ni) extracted from cathode material ofbattery cells. In the solution 141, the desirable materials remainingcommingled during precipitation such that the resulting cathode material134 has the correct proportion for usage in the new cells 140.

FIG. 3 is a diagram of charge flow (electrons) during charging anddischarging of the batteries of FIG. 1. Batteries in general produce anelectron flow via an electrochemical reaction that causes an electricalcurrent from the electron flow to provide the electrical power, coupledwith a corresponding flow of ions in the battery between an anode andcathode. Referring to FIGS. 1 and 3, a lithium-ion battery (LIB) 140′generates a negative electron flow 150 to power an electrical load 152in a reversible manner (for recharge), similar to other rechargeablebatteries. During charging, a charger 170 provides a voltage source thatcauses the electron flow 151′ to reverse. Lithium ions 154 move from thenegative electrode 160 to the positive electrode 162 during discharge,and back when charging. An anode tab 161 electrically connects thenegative electrodes 160 for connection to the load 152/charger 170, anda cathode tab 163 connects the positive electrodes 162. An electrolyte168 surrounds the electrodes for facilitating ion 154 transfer. Aseparator prevents contact between the anode 160 and cathode 162 toallow ionic transfer via the electrolyte 168 so that the anode andcathode plates do not “short out” from contact. The positive electrode162 half-reaction (cathode reaction), take LiCoO2 as an example:

LiCoO₂

Li_(1-x)CoO₂ +xLi+xe ⁻

The negative electrode 160 half-reaction is:

xLi⁺ +xe ⁻+6C

Li_(x)C₆

Overall Cell Reaction:

C+LiCoO₂

Li_(x)C+Li_(1-x)CoO₂

During charging, the transition metal cobalt is oxidized from Co³⁺ toCo⁴⁺, and reduced from Co⁴⁺ to Co³⁺ during discharge.

FIG. 4 is a diagram of battery structure of FIG. 1. Referring to FIGS. 3and 4, the physical structure of the cell 140 is a cylinderencapsulation of rolled sheets defining the negative electrode 160 andthe positive electrode 162.

Primary functional parts of the lithium-ion battery 140 are the anode160, cathode, 162 electrolyte 168, and separator 172. LIBs use anintercalated lithium compound as the electrode materials. The mostcommercially popular anode 160 (negative) electrode material containsgraphite, carbon and PVDF (polyvinylidene fluoride) binder, coated oncopper foil. The cathode 162 (positive) electrode contains cathodematerial, carbon, and PVDF binder, coated on aluminum foil. The cathode162 material is generally one of three kinds of materials: a layeredoxide (such as lithium cobalt or nickel oxide), a polyanion (such aslithium iron phosphate), or a spinel (such as lithium manganese oxide),and defines the cathode material 122 and recycled cathode material 132as disclosed herein. Alternatively, the disclosed approach for recyclingcathode material may be applied to other materials in various batterycomponents, such as anodic and electrolyte components. The electrolyte168 is typically a mixture of organic carbonates, generally usenon-coordinating anion salts such as lithium hexafluorophosphate(LiPF₆). The electrolyte 168 acts as an ionic path between electrodes.The outside metal casing defines the negative terminal 161′, coupled tothe anode tab 161, and the top cap 163′ connects to the cathode tab 163.A gasket 174 and bottom insulator 176 maintains electrical separationbetween the polarized components.

Conventional approaches for recycling focus on LiCoO₂ in spent LIBs.However, with the development of lithium ion battery technologies,different cathode materials are now being used to produce lithium ionbatteries such as LiCoO₂, LiFePO4, LiMnO₂, LiNi_(x)Co_(y)Al_(z) O₂ andLiNi_(x)Mn_(y) Co_(z) O₂. It can be complex to sort out lithium ionbatteries based on the battery chemistry and conventional methods cannoteffectively recycle lithium ion batteries with mixed chemistries becausedifferent procedures are required to separate the respective compoundsfor reuse as active cathode material.

The cathode materials widely used in commercial lithium ion batteriesinclude LiCoO₂, LiMn₂O₄, LiNiO₂, LiNi_(x)Co_(y)Al_(z) O₂,LiNi_(x)Mn_(y)Co_(z)O₂ and LiFePO₄. In order to recycle lithium ionbatteries effectively, it is beneficial to consider all the variousbattery chemistries. Thus, it is beneficial to develop a simpler andenvironmentally acceptable recycling process generally applicable tovarious widely used LIBs used widely. Configurations disclosed hereinpresent an example to extract compounds including the desirable elementsof Co, Ni, Mn, and Li from mixed cathode materials and utilize therecycled materials to produce active materials for batteries. Alternatechemistries may be recycled using the methods disclosed.

FIG. 5 is a diagram of recycling the cathode material in the battery ofFIG. 4. Referring to FIGS. 1, 4 and 5, at step 1 discharged Li ionbatteries 120 are crushed/shredded. Mechanical separation processes areapplied as a pretreatment to separate the outer cases and shells and theplastic fraction, as shown at step 1 a.

The sieved cathode powder will be leached by 4M sulfuric acid (H₂SO₄)and 29-32% hydrogen peroxide for about 2-3 hours at 70-80° C., asdepicted at step 2. Other concentrations of sulfuric acid may also beemployed. Addition of hydrogen peroxide H₂O₂ changes not only Fe2+ toFe3+, but also other metal ions Mn, Ni, Co to 2+, thus leading toseparate iron by controlling pH of the solution in step 3. Afterfiltration, residual LiFeO4 and carbon can be separated bycentrifugation, as shown at step 2 a. Other impurities are also removedfrom the surface of the solution, as shown at step 2 b.

The metallic elements of interest are transfer to the aqueous solutionas the crushed raw cathode materials form a granular mass 126 used togenerate the solution of aggregate battery materials from the spentcells, as depicted at step 3. This includes the desirable materials ofCo (cobalt), Ni (nickel), Mn (manganese), and Li (lithium in the exampleshown; other desirable materials may be employed using the presentapproach with alternate battery chemistries. The pH is adjusted toextract iron, copper and aluminum as Fe(OH)₃, Cu(OH)₂ and Al(OH)₃. Thisinvolves adjusting the pH to a range between 3.0-7.0. Accordingly, NaOHsolution is added to adjust pH number to deposit Fe(OH)₃, Cu(OH)2 andAl(OH)3 which have a lower solubility constant, and keep Mn²⁺, Co²⁺,Ni²⁺ in the solution, then Fe(OH)₃, Cu(OH)2 and Al(OH)3 are separated byfiltration. It should be noted that the above processes includemaintaining the solution 141 at a temperature between 40 deg. C. and 80deg. C., thus avoiding high heat required in conventional approaches.

The desirable materials are now dissolved in the solution 141. Based onthe predetermined target ratio of the desirable materials, the solutionis adjusted to achieve the predetermined ratio of desirable materials.In the example approach, this is a 1:1:1 combination of cobalt,manganese and nickel, although any suitable ratio could be employed.Therefore, adjusting the solution includes identifying a desired ratioof the desirable materials for use in recycled cathode materialresulting from the generated solution 141, and adding raw materials 142to achieve the desired ratio, such that the raw materials includeadditional quantities of the desirable materials and subsequently addingthe new raw materials to attain the predetermined ratio. Adding the rawmaterials includes adding additional quantities of the desirablematerials for achieving the desired ratio without separating theindividual desirable materials already in solution form, therefore themixed desirable materials (Co, Mn, Ni) do not need to be separatelydrawn or extracted as in conventional approaches, which usually involvehigh heat to break the molecular bonds of the compounds. Furthermore, inan alternate configuration, selected metallic elements can be separatedfrom the solution, which can be used to synthesize particular cathodematerials. Therefore, the pH may be adjusted to extract one or moremetal ions or other elements prior to adjusting the solution for thepredetermined ratio of desirable materials, and subsequent extract theremaining desirable materials in the predetermined ratio.

Rather, the concentration of Mn²⁺, Co²⁺, Ni²⁺ in the solution is tested,and adjusted the ratio of them to 1:1:1 or other suitable ratio withadditional CoSO₄, NiSO₄, MnSO₄. NaOH solution is added to increase thepH to around 11, usually within a range of 10.0-13, thus adjusting a pHof the solution such that the desirable materials for the new (recycled)charge materials precipitate. Ni_(1/3)Mn_(1/3)Co_(1/3)(OH)₂ orNi_(1/3)Mn_(1/3)Co_(1/3)O(OH) or a mixture thereof can be coprecipitatedsuch that the respective mole ratio is 1:1:1, as depicted at step 4.Ni_(x)Mn_(y)Co_(z)(OH)₂ or Ni_(x)Mn_(y)Co_(z)O(OH) or a mixture withdifferent ratios of x, y, and z can also be precipitated. Na₂CO₃ isadded in the solution to deposit Li₂CO₃, as depicted at step 5. Finally,the recovered Ni_(1/3)Mn_(1/3)Co_(1/3)(OH)₂ and Li₂CO₃ are sintered toproduce the cathode material.

In the example arrangement, the desirable materials include manganese(Mn), cobalt (Co), and nickel (Ni) extracted from charge material 122 ofthe spent battery cells 120, in which the desirable materials remaincommingled in the solution 141 during precipitation. Adjusting the pHincludes adding a substance, such as NaOH (sodium hydroxide, alsoreferred to as lye or caustic soda) for raising the pH such that thedesirable materials precipitate, however any suitable substance forraising the pH may be employed. The end result is that adjusting the pHincludes adding sodium hydroxide for raising the pH to permitprecipitation of the desirable materials for use as cathode precursormaterial without separately precipitating the individual compoundsdefining the desirable materials. The precipitation of the desirablematerials occurs at temperatures below 80 deg. C., avoiding high heatrequired in conventional approaches. It should be further noted that, incontrast to conventional approaches, the desirable materials remaincommingled during precipitation as a combined hydroxide (OH), (OH)₂ orcarbonate (CO₃). The addition of the additional charge materials foradjusting the ratio achieves the desired molar ratio for the resultingrecycled battery. The intermediate, or precursor form will result in alithium oxide form following sintering with lithium carbonate Li₂CO₃.

Na₂CO₃ is added in the solution to deposit Li₂CO₃ at about 40° C. Afterfiltrating, Li₂CO₃ can be recycled as the starting material to synthesisthe active cathode material LiNi_(1/3)Mn_(1/3)Co_(1/3)O₂, as shown atsteps 5 and 5 a. Therefore, the method adds back the lithium to theprecipitated desirable materials to form active cathode materialsuitable for the new battery, and precipitates the desirable material inthe predetermined ratio to form charge material for a new battery 140having the predetermined ratio of the desirable materials.

The coprecipitated materials Ni_(1/3)Mn_(1/3)Co_(1/3)(OH)₂ orNi_(1/3)Mn_(1/3)Co_(1/3)O(OH) or their mixture and recovered Li₂CO₃,with additional Li₂CO₃ in molar ratio 1.1 of Li versus M(M=Ni_(1/3)Mn_(1/3)Co_(1/3)), are mixed and grinded in mortar, asdepicted at step 6. The mixture may be reformulated by any suitableprocessing to form the active cathode material 134 for new batteries140. In the example approach, the mixture was sintered at 900 for 15hours. The reaction product may be ground into powder for subsequentdistribution and reformation into new cells 140. TheLiNi_(1/3)Mn_(1/3)Co_(1/3)O₂ is sintered by a high temperaturesolid-state method at 900° C. for 15 hours.

Battery chemistries including aluminum (Al) are becoming popular forapplications such as electric vehicles, using chemistry such asLiNiCoAlO₂. Conventional approaches for recovering active materials fromlithium ion batteries with chemistry LiNiCoAlO₂ in a manner that can beused to make new active materials for new lithium ion batteries havebeen met with several shortcomings. Conventional processes cannotrecover transition metals from LiNiCoAlO₂ in such a form that they canbe used to make new cathode materials for LNiCoO₂ or LiNiCoAlO₂batteries without using expensive organic reagents. The recoveredprecursor material NiCoAl(OH)₂ or NiCo(OH)₂ can be used for making newLiNiCoAlO₂ or LiNiCoO₂ cathode materials. This may include addingAl(OH)₃ to the precipitated material and/or Ni, Co, or Al sulfates tothe solution prior to precipitation. One specific example is thatsolution of nickel and cobalt sulfates was from recycled material.Al₂(SO₄)₃.18H₂O as Al starting material was dissolved in distilledwater. Subsequently, chelating agent 5-sulfosalicylic acid was dissolvedin the solution of aluminum sulfates. Solutions of transition metalsulfates, aluminum sulfate, ammonia, and NaOH were pumped into acontinuous stirred tank reactor. Total concentration of solutions of themetal sulfates was 1.5 M or other concentrations. Concentration of thechelating agent is 0.05M-0.5M. pH was controlled 10-pH. Stirring speedwas 500-1000 rpm and the temperature was controlled in 30-60° C. Afterthe reaction, NiCoAl(OH)₂ co-precipitate was filtered, washed and dried.The metal hydroxide co-precipitate precursor was mixed with 5% excesslithium carbonate thoroughly. The mixture was at first calcined at 450°C. for 4-6 h in air, and then sintered at 750-850° C. for 15-20 h in anoxygen atmosphere or air to obtain LiNi_(x)Co_(y)Al_(z)O2 powder to formcharge material suitable for use in new batteries.

For such a recycling operation, it is desirable that the batteries be ofa single stream chemistry (LiNiCoAlO₂) however if there are otherchemistries present in the LiMO₂ (where M is manganese, as well as Ni,Al and Co), the manganese can be removed from solution. Ni, Co and Alcan be used to precipitate precursor and synthesize cathode materials.

For the recovery and synthesis of LiNiCoAlO₂ there are at least twoapproaches. FIG. 6 is a process flow diagram of recycling lithium ionbatteries. FIG. 7 is a process flow for an alternate configuration ofrecycling lithium ion batteries using aluminum hydroxide.

Referring to FIG. 6, in order to undergo the recovery process, thecathode powders must be separated from the batteries/current collectors.Physical agitation of spent cell materials are used to extract cathodematerial by leaching crushed spent battery materials in a sealed systemor containment to separate current collectors in a solution, as depictedat step 601. An example method of how this could be done is by shreddingand sizing. Then the powders can be leached into solution using acombination of sulfuric acid and hydrogen peroxide, thus leaching mayinclude forming a solution from addition of at least one of hydrogenperoxide and sulfuric acid. Impurities can be removed by adjusting a pHof the solution for removing impurities by precipitating hydroxides andfiltering. This may be performed by increasing the pH to 5-7,precipitating the respective hydroxides and filtering, as disclosed atstep 602. Aluminum hydroxide may also be removed in this step. At step603, Mn ions in the solution can also be removed by adding suitablechemicals. The concentration of ions in solution will be measured andadjusted to the desired ratio based on the industrial needs. Thisincludes adding at least one of Ni, Co and aluminum salts based on adesired composition of resulting recovered charge materials, as depictedat step 604. It may be desirable to increase the pH above 7 prior toadding Al(SO4)₃ or Al(OH)₃ or other aluminum salts to the solution.Precursor materials may then be recovered by precipitating using atleast one of sodium hydroxide or potassium hydroxide, as shown at step605. Sintering the recovered precursor materials with lithium carbonateforms active cathode material, as depicted at steps 606 and 607. Theprecipitate from step 605 can be sold to material or batterymanufacturers or can then be mixed and sintered with the lithiumcarbonate to form active LiNiCoAlO₂.

In an alternate configuration, depicted in FIG. 7, no aluminum is addedto solution and Al(OH)₃ is added to the material after precipitation,after mixing it is sintered with lithium carbonate to form the activematerial. Therefore, referring to FIG. 7, steps 701-703 proceed as theircounterparts in FIG. 6. If it is desirable to recover LiNiCoO₂ materialthe procedure follows FIG. 6 but no aluminum is added back into thesolution or precipitate. Accordingly, the process includes adding onlyNi or Co prior to precipitating the recovered charge materials at step704. The process defers addition of aluminum hydroxide (step 706) untilafter precipitation (step 705) and before sintering at step 708. Ingeneral, using the processes depicted in FIGS. 6 and 7, active chargematerial formed includes LiNixCoxAlzO2 where x, y and z are integersdefining the composition of the resulting active charge material. Othermaterials including Cu, Al, steel, carbon, lithium carbonate, and othermaterials including transition metals can also be recovered

In an alternate arrangement, the above approaches converge to a singlestream recycling process including both Ni/Mn/Co (NMC) and Ni/Co/Al(NCA) chemistries, by recognizing the common aspects of pH changes andrecombining pure (virgin) cathode materials to form a combined precursorhaving a molar ratio based on the chemistry requirements for the new,recycled cathode materials.

FIG. 8 is a process flow diagram for a combined recycling process forboth Ni/Mn/Co and Ni/Co/Al batteries for any suitable molar ratio. Inthe approach of FIG. 8, the following benefits are achieved:

1. Both LiNi_(x)Mn_(y)Co_(z)O₂ and LiNi_(x)Co_(y)Al_(z)O₂ are cathodematerials for Li-ion batteries. These cathode materials can besynthesized in the recycling process. These recovered cathode materialshave similar performance with the virgin materials and can be used tomake new batteries.

2. In the flow chart of FIG. 8, both LiNi_(x)Mn_(y)Co_(z)O₂ withdifferent ratio of Ni, Mn and Co, and LiNi_(x)Co_(y)Al_(z)O2 withdifferent ratio of Ni, Co and Al are recovered. LiNi_(x)Mn_(y)Co_(z)O2and LiNixCoyAlzO2 can be synthesized by sintering their carbonates orhydroxides with Li₂CO₃. In our previous patent, LiNi_(x)Mn_(y)Co_(z)O2is synthesized by sintering Ni_(x)Mn_(y)Co_(z)(OH)₂ and Li₂CO₃. Itshould be noted that both the elemental composition (e.g. NMC or NCA)and the molar ratio of those elements are determined both by the molarratios following leaching, and the addition of pure raw materials to theleached solution, designated by the subscripts x, y, z specifying therespective molar ratios. Other suitable battery chemistries may beformed using the disclosed approach.

3. Based on the recycling stream, LiNi_(x)Mn_(y)Co_(z)O2 orLiNi_(x)Co_(y)Al_(z)O2 can be synthesized. If the recycling streamincludes Mn based batteries or Mn compound is added, LiNixMnyCozO2 issynthesized. If the recycling stream does not include Mn based batteriesor Mn is removed, LiNixCoyAlzO2 is synthesized.

4. For both LiNixMnyCozO2 and LiNixCoyAlzO2, impurities can be removedby increasing the pH to 5-7, precipitating their hydroxides andfiltering.

5. The carbonate and hydroxide precursor precipitates can be obtained bycontrolling their solubility in the solution.

In FIG. 8, the processing of the recycling stream for generating newcharge material for the recycled battery is shown. The method forrecycling lithium-ion batteries, comprising includes, at step 801,receiving a recycling stream of expended, discarded and/or spent lithiumion batteries, and agitating the batteries to expose the internalcomponents and charge material by physical crushing, shredding and/ordisengagement to provide surface area open to liquid exposure, asdepicted at step 802.

Physical sieving and filtering remove casing, separators and largeextraneous materials at step 803, and an acid leaching process commencedat step 804. A leached solution is formed by combining crushed batterymaterial from the lithium battery recycling stream with an acidic leachagent and hydrogen peroxide (H₂O₂) to separate cathode materials fromundissolved material, as depicted at step 804. A low pH solvent bath,leach liquor or other suitable combination immerses the agitatedmaterials of the recycling stream for dissolving the cathode materialssuch as Ni, Mn, Co and Al. The acidic leach agent may be concentrationof sulfuric acid in the range of 2-5 M (molar), and in a particulararrangement, the acidic leach agent is 4M sulfuric acid.

A particular feature of the disclosed approach is adaptability tovarious target chemistries for the recycled batteries, and sourced fromvarious unknown chemistries in the recycling stream. Design or demandspecifications determine material parameters for a recycled battery byidentifying a molar ratio and elements of cathode materialscorresponding to a charge material chemistry of a recycled battery.Battery usage as directed by a customer, for example, may be anoverriding factor, such as automotive electric or hybrid vehicle usage,portable electronic devices, etc. The identified battery chemistry,specifying particular elements and molar ratios, results in the specificelectrical characteristics of the recycled batteries produced by thedisclosed approach.

Following dissolution in the leach solution, a test or sample isemployed to determine a composition of the leach solution by identifyinga molar ratio of the ions dissolved therein, thus clarifying thepreviously unknown collective composition of the input recycling stream.Recall that all charge material has remained comingled in the leachsolution-extraction or precipitation of individual elements has not beenrequired.

Based on the determined composition, Ni, Co, Mn or Al salts in a sulfate(xSO₄) or hydroxide (xOH) form are added to the leach solution to adjustthe molar ratio of the dissolved cathode material salts in the leachsolution to correspond to the identified molar ratio for the recycledbattery. Depending on the expected battery chemistry, for example, a NMCchemistry with 1:1:1 ratio may be sought, or alternatively, a NCAchemistry with 1:2:1. Any suitable ratio and combination of chargematerials may be selected. One particular selection may be thedetermination of whether manganese (Mn) is included or whether NCAmanganese-free formulation will be employed.

Prior to adjusting the molar ratio, impurities may be precipitated fromthe leach solution by adding sodium hydroxide until the pH is in a rangebetween 5.0-7.0 for precipitating hydroxide forms of the impuritiesoutside the determined material parameters, as depicted at step 805.

The determined battery chemistry and source recycling stream results ina decision point from step 805. If the chemistry for the recycledbattery include manganese (Mn), then the cathode material salts includeNi, Mn and Co in a hydroxide form, as depicted at step 806. Otherwise,if the recycled battery is devoid of Mn, then the cathode material saltsinclude Ni, Co and Al in a hydroxide form, as shown at step 809. In thenon-Mn formulation, prior to adding raw material for adjusting the molarratio, manganese ions may be removed from the leach solution.

Following the branch at step 805, in general, sodium hydroxide is addedfor raising the pH of the leach solution to at least 10 forprecipitating and filtering metal ions of the cathode materials to forma charge material precursor by coprecipitating the Ni, Co, Mn and Alsalts remaining in the leach solution as a combined hydroxide (OH),(OH)₂ or carbonate (CO₃) having a molar ratio corresponding to theidentified molar ratio for the recycled battery, the charge precursormaterial responsive to sintering for forming active cathode materials inan oxide form following sintering with lithium carbonate (Li2CO₃).

In either step, charge precursor material is generated by raising the pHto a range of 10-13.0 for precipitating hydroxide charge material, andmore specifically, may include raising pH by adding sodium hydroxide toincrease the pH to 11.0, as depicted at steps 807 and 810. The resultingcharge material precursor has the form NixMnyCoz(OH)2, NixMnyCozCO3,NixCoyAlz(OH)2 or NixCoyAlzCO3 where the molar ratios defined by x, y,and z are based on the determined material parameters of the recycledbattery, as depicted at steps 808 and 811.

In a more general sense, the aluminum sulfate is mixed with a chelatingagent, and the aluminum sulfate solution and nickel cobalt sulfatesolutions are added with ammonium water and sodium hydroxide to areactor. A pH monitor constantly monitors and releases additional sodiumhydroxide to maintain the pH at 10.0 or other suitable pH to result incoprecipitation of the NCA precursor.

The generalized process of FIG. 8 is intended to accommodate Al basedbattery chemistries without Mn, but may also be used for any suitableformulation by modifying the molar ratios at steps 806 or 809, asapplicable.

Recycling of various types of battery chemistries present in therecycling stream may benefit from the approach herein. LIBs based onlithium cobalt oxide (LiCoO2), offer high energy density but presentsafety risks, especially when damaged. Lithium iron phosphate (LiFePO4),lithium ion manganese oxide battery (Li2Mn2O4, LiMnO2, or LMO), andlithium nickel manganese cobalt oxide (LiNiMnCoO2 or NMC) offer lowerenergy density but longer lives and less likelihood of unfortunateevents in real-world use (e.g., fire, explosion, etc.).

FIG. 9 shows an alternative configuration for processing residual chargematerial as in FIG. 8. As indicated above, conventional approaches torecycling suffer from the shortcoming of restriction to a particularbattery chemistry and proportions within that chemistry. Theconfigurations above facilitate recycling directed to any suitableproportion of charge material independent of the proportion of theincoming stream. However, following the acid leach step for dissolvingcathode materials, residual charge materials of other chemistries inlithium ion batteries may still remain. For example, after sulfuric acidis employed to dissolve nickel, manganese and cobalt (NMC) for newbatteries, residual charge material of lithium iron phosphate batteriesremains, along with undissolved graphite and carbon.

Conventional approaches discard lithium iron phosphate because it isdifficult to achieve cost effectiveness for recycling. However,following leaching with sulfuric acid and pH adjustment with hydrogenperoxide, iron phosphate (FePO₄) remains, along with graphite andcarbon, as a powdery residue. The approach of FIGS. 8 and 9 performscost-effective recycling of these normally discarded materials.

Li-ion batteries including different streams were used in the recyclingprocess. These batteries could include GM® Volt cells (Lithium ManganeseOxide, or LMO+NMC chemistry), electronics batteries (Mainly LCO, orLithium Cobalt Oxide chemistry) and purchased batteries with LFP(Lithium Iron Phosphate) and NCA chemistry. These Li-ion batteries withmixed chemistry are processed by discharging, shredding, magneticseparation and sieving. Recycling including the following leachingprocess occurs, such that different cathode materials are leached intothe acid solution, defined by the following reactions:

2LiCoO2+3H2SO4+H2O2==Li2SO4+2CoSO4+O2+H2O

2LiMn204+5H2SO4+H2O2==Li2SO4+4MnSO4+2O2+6H2O

6LiNi0.33Mn0.33CoO.33O2+9H2SO4+H2O2==2MnSO4+2NiSO4+2CoSO4+3Li2SO4+2O2+10H2O

LiNiCoAlO2+H2SO4==Li2SO4+NiSO4+CoSO4+Al2SO4+H2O

2LiFePO4+H2SO4+H2O2==Li2SO4+2FePO4+2H2O

Note: The above equations include compounds with the followingnomenclature, also discussed further below:

-   -   lithium iron phosphate: LiFePO₄    -   Iron phosphate, also ferric phosphate FePO₄    -   Phosphoric acid: H₃PO₄    -   Ammonium hydroxide: NH₄OH    -   Sodium hydroxide NaOH    -   Iron(III) chloride (ferric chloride): FeCl₃        Another common battery chemistry includes the lithium-ion        battery, which is also a rechargeable type of battery but made        with lithium iron phosphate (LiFePO4) as the cathode material.        Generally, anodes are made up of graphite in lithium ion        batteries. From the recycling process of FIGS. 5 and 8, and the        equations above, all the cathode materials except LiFePO₄ can be        dissolved into the acid solution and utilized to synthesize NMC        charge material. LiFePO₄ is precipitated as FePO₄ and remains        from the previous NMC recycling process shown in FIGS. 5 and 8.        Graphite and conductive carbon are not dissolved into the        solution. Therefore, by filtration, the mixture of FePO₄,        graphite and conductive carbon can be extracted from the        remainder, however conventional recycling processes simply        discarded these materials. In contrast, however, in the        configurations below, FePO4 can be separated from graphite and        carbon, and FePO4 can be used to synthesize LiFePO4, and        graphite can be regenerated. This will increase the profit        margin of the recycling process and increase the sustainability        of the recycling process.

FIG. 9 shows the separation and recovery process 900 for LiFePO₄ andgraphite as an extension of the leaching process of FIGS. 5 and 8, atstep 902. Referring to FIGS. 5 and 9, at step 904, the residual mixturefrom FIG. 5, steps 2 a and 2 b is leached in an HCl solution and FePO4is dissolved as FeCl3 and H3PO4 solution through the following reaction:FePO4+3HCl=FeCl3+H3PO4 (phosphoric acid), depicted at step 906. The ironchloride/phosphoric acid solution is used to synthesize FePO4 which isthe precursor of LiFePO4.

The recovered FeCl3 solution and H3PO4 solution is used to precipitateFePO4 by adjusting the pH to recover iron phosphate. according to thefollowing reaction:

If a concentrated NH4OH solution is used,

2FeCl3+2H3PO4+7NH4OH═(NH4)Fe2(OH)(PO4)2.2H2O+6NH4Cl+4H2O

If dilute NH4OH solution is used, FeCl3+H3PO4+3NH4OH═FePO4+3NH4Cl+3H2O

(NH4)Fe2(OH)(PO4)2.2H2O particles may be heated at 400° C. for 8 hoursto generate FePO4.

If an NaOH (sodium hydroxide) solution is employed to adjust pH, theyield is a FePO4 particles via the reaction:

FeCl3+H3PO4+3NaOH=FePO4+3NaCl+3H2O

By controlling the experimental conditions, primary particles orsecondary particles can be formed. Secondary particles are theagglomerate of the primary particles. The significance of the primaryparticles vs. the secondary particles is that the secondary particlesare larger relative to the primary particles. The primary particles aresmall nanoparticles that tend to be attracted to each other, which canaffect uniformity of the resulting lithium iron phosphate. Secondaryparticles generally present better uniformity. Sodium hydroxide andammonium hydroxide both operate similarly for controlling pH, howeverammonium hydroxide as the complexing agent tends to form more secondaryparticles. Little or no secondary particles have been observed whenusing NaOH to control the pH.

Heating to 400° C. is effective for removing NH4+, OH— ions and water inthe precursor (NH4)Fe2(OH)(PO4)2.2H2O to form the pure FePO4. However,heating may be omitted if similar electrochemical properties result bysintering LFP by FePO4 and (NH4)Fe2(OH)(PO4)2.2H2O. In contrast, the useof NaOH to control the pH directly results in FePO4 receptive tosintering.

From the solution of step 906, precipitated FePO4 results, as shown atstep 908, which can be used as the precursor to synthesize LiFePO4. Acarbon source (for example sucrose, or glucose) may also be added intothe mixture, such that LiFePO4 and a carbon composite can besynthesized, discussed further below in FIG. 10. The LiFePO4 cathodematerial is synthesized from FePO4 and Li2CO3, as shown at step 910. Amolar ration used in the ball milling may be adjusted as follows. Amolar ratio of Li:Fe:P:C=1.05:1:1:1.05, may be employed for reducing andcoating. Alternatively, a molar ration of Li: Fe: P: C=1.05:1:1:0.25,may be employed for reducing only. In the reduction only scenario, itmay be beneficial to add additional carbon to ensure that the Fe(III) isreduced to Fe(II). This is followed by ball milling for around 2 hours,and sintering the mixture at 700° C. for 16 hours in a nitrogenatmosphere. If sucrose or glucose is added with FePO4, and Li2CO3,LiFePO4/C composite can also be synthesized.

FIGS. 10a-b are a flowchart for a particular configuration for recyclinglithium iron phosphate (LiFePO4) from the residual charge material ofFIG. 9. Referring to FIGS. 5, 9 and 10, the method for recycling lithiumiron phosphate batteries as disclosed herein includes, at step 1002,removing solid battery components including casing and electrodematerials from exhausted lithium ion batteries (LIBs) by physicalseparation resulting in a granular mass of exhausted charge materialsincluding carbon, graphite and iron phosphate. An NMC recycling processinvolves adding a first inorganic acid, such as sulfuric acid, to thegranular mass for leaching charge materials other than iron phosphatefrom the exhausted charge materials, as depicted at step 1004. Thiscorresponds with the leaching of NMC charge materials shown in FIG. 5.Alternate inorganic acids, or mineral acids, may also be employed;examples of inorganic acids include: hydrochloric acid, sulfuric acid,phosphoric acid, nitric acid, boric acid, hydrofluoric acid, hydrobromicacid, perchloric acid and hydroiodic acid. The first acid leachingrecovers charge material compounds other than iron phosphate from thegranular mass prior to adding the second inorganic acid, as depicted atstep 1006. The NMC leached solution passes on to the remaining steps ofFIG. 5, thus directing a leach solution resulting from the leachedcharge materials to a recycling stream as depicted at step 1008.

The remainder of material unreacted/unleached by the first inorganicacid now remains, defined by a granular mass. A second inorganic acid isto the granular mass to separate graphite and carbon from the ironphosphate to yield a solution of iron chloride and phosphoric acid withundissolved carbon and graphite, as shown at step 1010. In the exampleconfiguration shown, the inorganic acid is 5M hydrochloric acid, asshown at step 1012.

A second leach solution now results for recycling the remainingunleached residual mass from the first sulfuric acid leach. The pH ofthe iron chloride and phosphoric acid solution is adjusted toprecipitate an iron phosphate precursor using either ammonium hydroxideor sodium hydroxide, as shown at step 1014. The precursor, FePO4.xH2O,may be synthesized in a tank reactor with a heating jacket. The solutionis slowly pumped (2. 7 ml/min) into a continuous stirred (650 rpm) tankreactor and the circulation system filled with water heated at 90° C. Atthe same time, a 32 wt. % NH4OH solution is added to control the pHaround 2. This includes precipitating the iron phosphate by circulatingand heating the reactor containing the iron chloride and phosphoric acidsolution to precipitate iron phosphate in a powder form, as shown atstep 1016.

A check is performed, at step 1018, to determine if pH adjustment ispreferred. If so, then ammonium hydroxide is added to the reactor formaintaining the pH substantially at 2, as shown at step 1020. This mayinclude controlling the pH in a range between 2.0-2.3, or optionallybetween 1.5-4.5, as depicted at step 1022.

Lithium carbonate is combined with the precipitated iron phosphate byagitation, as depicted at step 1024. This includes adding astoichiometric amount of lithium carbonate to the yield the lithium ironphosphate charge material, as disclosed at step 1026.

A check is performed, at step 1028, to determine if carbon compositesare desired. This may include combining a carbon source and lithiumcarbonate with the precipitated iron phosphate by agitation, in whichthe carbon source includes at least glucose or sucrose, as depicted atstep 1030. In the example arrangement, the added carbon source is anamount based on 20% of the iron phosphate, as shown at step 1032.Sintering of the combined mixture of lithium carbonate and ironphosphate then yields cathode powders adapted for use as chargematerials, as depicted at step 1034

The disclosed approach implements a second leach operation following afirst leach operation, using different leach agents, inorganic acidsincluding sulfuric acid and hydrochloric acid, respectively. The examplearrangement adds a second inorganic acid to the remaining granular massto generate a leach solution including iron chloride iron phosphate, andalso to leave carbon and graphite undisturbed. The pH of the leachsolution is adjusted to precipitate an iron phosphate precursor, suchthat the iron phosphate precursor is responsive to lithium carbonate andsintering for forming lithium iron phosphate.

Each leach agent, therefore, targets specific charge materials. For thefirst leach operation, the leach solution is formed from the firstinorganic acid by adding an inorganic acid to crushed battery materialsdefining the granular mass to form a leach solution including compoundsof nickel, manganese and cobalt reacted with the inorganic acid. Asdisclosed above, when the first inorganic acid is sulfuric acid, theleached charge materials include nickel, manganese and cobalt. Followingremoval of the exhausted charge materials including nickel, manganeseand cobalt from dissolution in the leached charge materials, anunreacted granular mass remains for the second leach operation. Thesecond operation allows recycling of materials that may not be feasiblealone because the process has been commenced in favor of the first leachoperation.

Similarly, following step 1010, graphite and carbon remain. Afterfiltration, the mixture of graphite and carbon can be collected. Themixture is washed and dried. Then the mixture is heated at differenttemperatures in air. There are two purposes for heating the mixture. 1.Heating can remove remaining impurities. 2. Heating can also crystallizethe graphite. By controlling different heating temperature, bothgraphite and carbon are not burned and the mixture can be used to formthe anode directly.

The separation of graphite and carbon can be performed by twoapproaches. 1. Burning. The burning temperature for graphite and carbonis different. By choosing an optimal temperature, carbon burns to leavea graphite remainder, which can be used as anode materials for lithiumion batteries. 2. Sieving. In lithium ion batteries, graphite isnormally a microsize powder and carbon is a nanosize powder. By sieving,carbon can be separated from graphite using screens of different meshsize.

While the system and methods defined herein have been particularly shownand described with references to embodiments thereof, it will beunderstood by those skilled in the art that various changes in form anddetails may be made therein without departing from the scope of theinvention encompassed by the appended claims.

What is claimed is:
 1. A method for recycling lithium iron phosphatebatteries, comprising removing solid battery components including casingand electrode materials from exhausted lithium ion batteries (LIBs) byphysical separation resulting in a granular mass of exhausted chargematerials including carbon, graphite and iron phosphate; adding aninorganic acid to the granular mass to separate graphite and carbon fromthe iron phosphate to yield a solution of iron chloride and phosphoricacid with undissolved carbon and graphite; adjust a pH of the ironchloride and phosphoric acid solution to precipitate an iron phosphateprecursor; combining lithium carbonate with the precipitated ironphosphate by agitation; and sintering the combined mixture of lithiumcarbonate and iron phosphate to yield cathode powders adapted for use ascharge materials.
 2. The method of claim 1 further comprising sinteringthe combined mixture to generate LiFePO₄ charge material.
 3. The methodof claim 1 further comprising precipitating the iron phosphate bycirculating and heating a reactor containing the iron chloride andphosphoric acid solution to precipitate iron phosphate in a powder form.4. The method of claim 1 further comprising combining a carbon sourceand lithium carbonate with the precipitated iron phosphate by agitation,the carbon source including at least glucose or sucrose.
 5. The methodof claim 4 further comprising adding carbon source in an amount based on20% of the iron phosphate.
 6. The method of claim 1 wherein theinorganic acid is 5M hydrochloric acid.
 7. The method of claim 1 furthercomprising adding ammonium hydroxide to the reactor for maintaining thepH substantially at
 2. 8. The method of claim 7 further comprisingcontrolling the pH in a range between 1.5-4.5.
 9. The method of claim 1further comprising adding a stoichiometric amount of lithium carbonateto the yield the lithium iron phosphate charge material.
 10. The methodof claim 1 further comprising acid leaching charge material compoundsother than iron phosphate from the granular mass prior to adding theinorganic acid.
 11. The method of claim 1 further comprising adjustingthe pH from the addition of ammonium hydroxide or sodium hydroxide. 12.A method for recycling lithium iron phosphate batteries, comprisingremoving solid battery components including casing and electrodematerials from exhausted lithium ion batteries (LIBs) by physicalseparation resulting in a granular mass of exhausted charge materialsincluding carbon, graphite and residual cathode materials; adding afirst inorganic acid to the granular mass for leaching charge materialsother than iron phosphate from the exhausted charge materials; directinga leach solution resulting from the leached charge materials to arecycling stream; adding a second inorganic acid to the remaininggranular mass to generate a leach solution including iron chloride andphosphoric acid and leave carbon and graphite undisturbed; adjusting thepH of the generated leach solution to precipitate an iron phosphateprecursor, the iron phosphate precursor responsive to lithium carbonateand sintering for forming lithium iron phosphate.
 13. The method ofclaim 12 wherein the second inorganic acid is hydrochloric acid.
 14. Themethod of claim 12 wherein the first inorganic acid is sulfuric acid,and the leached charge materials include nickel, manganese and cobalt.15. The method of claim 12 wherein the physical separation includes:agitation and crushing to separate casing and containment materials;sorting and magnetic separation to remove casing and current collectormetals from the charge material.
 16. The method of claim 12 furthercomprising removing exhausted charge materials including nickel,manganese and cobalt from dissolution in the leached charge materials.17. The method of claim 12 further comprising forming a leach solutionby adding an inorganic acid to crushed battery materials defining thegranular mass to form a leach solution including compounds of nickel,manganese and cobalt reacted with the inorganic acid.
 18. The method ofclaim 17 further comprising processing the leach solution for forming aparallel recycling stream for recycling the leached charge materials.19. The method of claim 12 wherein the first inorganic acid dissolves atleast one of nickel, manganese and cobalt charge materials and issubstantially nonreactive with the iron phosphate charge materials.